Anisotropic Bulk Magnet Composition for Ce Cost and Coercivity Tradeoff
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Solution Overview
Problem
The challenge is to develop an anisotropic bulk magnet with improved magnetic properties, particularly coercivity and maximum magnetic energy product, while addressing the limitations of using Ce instead of Nd, which leads to reduced magnetic properties due to the formation of a REFe2 phase and poor crystal grain alignment.
Innovation Solution
An anisotropic bulk magnet with a composition of ReaCebTicFe100-a-b-c-d-eMdBe, where Re includes Nd, Sc, Y, La, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, and M includes Ga, Co, Al, Cu, Nb, Si, Zr, Ta, V, Mo, Mn, Zn, Ni, Cr, Pb, Sn, In, Mg, Ag, Ge, with specific atomic percentages and Ti content within defined ranges, is manufactured through a process involving magnetic powder preparation, pressure sintering, and hot deforming to enhance (Re,Ce)2(Fe,Ti)14B phase and reduce (Re,Ce)Fe2 phase, resulting in fine crystal grains and improved alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If Ce is added instead of Nd to reduce cost, then production cost decreases, but magnetic properties deteriorate due to formation of REFe2 phase
Solution Approach 1:
The patent changes the chemical composition parameters by adding Ti to form (Re,Ce)2(Fe,Ti)14B main phase and controlling the ratio of rare earth elements. This parameter change suppresses the formation of REFe2 secondary phase while maintaining cost reduction benefits from Ce substitution, thereby resolving the contradiction between cost and magnetic properties
Solution Approach 2:
The patent creates a composite magnetic material system combining multiple rare earth elements (Re and Ce) with Fe, B, and Ti. This composite approach allows optimization of both cost (through Ce substitution) and magnetic properties (through controlled phase composition), resolving the contradiction between economic and performance requirements
2Quantity of substance
If Ce is added instead of Nd, then production cost decreases, but coercivity decreases due to high melting point of CeFe2 phase preventing crystal grain alignment
Solution Approach 1:
The patent modifies the compositional parameters by incorporating Ti and controlling the rare earth element ratio to suppress CeFe2 phase formation. This parameter change eliminates the harmful effect of high melting point CeFe2 phase on coercivity while preserving the cost advantage of Ce substitution
Solution Approach 2:
The patent converts the potential harm of Ce addition (formation of CeFe2 phase) into a benefit by controlling the composition to form desirable (Re,Ce)2(Fe,Ti)14B main phase. The Ce element, which would normally create harmful CeFe2 phase, is instead utilized to enhance the main phase properties while maintaining cost reduction, thus converting harm into benefit
3Quantity of substance
If Ce is added instead of Nd, then production cost decreases, but maximum magnetic energy product decreases due to reduced fractions of RE-rich phase and (Nd,Ce)2Fe14B main phase
Solution Approach 1:
The patent optimizes compositional parameters by adding Ti and controlling rare earth element ratios to maximize the fraction of (Re,Ce)2(Fe,Ti)14B main phase. This parameter optimization ensures high maximum magnetic energy product while maintaining the cost benefits of Ce substitution, resolving the contradiction between cost and performance
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves an anisotropic bulk magnet with high (Re,Ce)2(Fe,Ti)14B phase fraction, low (Re,Ce)Fe2 phase fraction, fine crystal grain size, and enhanced crystal grain alignment, leading to superior coercivity and maximum magnetic energy product.
Implementation Method 1
preparing an isotropic bulk magnet by pressure sintering the magnetic powder
Implementation Method 2
performing anisotropic bulking by hot deforming the isotropic bulk magnet
Implementation Method 3
hot deforming the isotropic bulk magnet
Data Source
AI summary
The present disclosure relates to an anisotropic bulk magnet and a method for manufacturing the same. The anisotropic bulk magnet has a high fraction of a (Re,Ce)2(Fe,Ti)14B phase (magnetic phase), a low fraction of a (Re,Ce)Fe2 phase (non-magnetic phase), a fine crystal grain size, an excellent degree of crystal grain alignment, and a high rare earth element content at an interface of the crystal grain, and therefore, may have excellent magnetic properties such as coercivity and maximum magnetic energy product.